circuit diagram and parts to repair 24 volt 20 amp battery charger uses Scr's?

I have a MAC 242011 battery charger  ( 24 volt 20 amp automatic battery charger

I need a source and a cct diagram to repair .

the Scrs are not working .

can you help ?

paulttq@yahoo.com

I am in Ottawa Canada
tel cell leave txt message 613 291 9942